It is customary practice in the construction industry related to the forming of a concrete structure to rely upon a mold of some type to form a desired volumetric cavity for the concrete to be disposed into and thus the concrete curing into the desired shape to form a concrete structural element. This necessitates the creating or assembling of a number of various molds in a multitude of desired shapes and then subsequently disassembling these molds after the concrete has been disposed into or poured into the uniquely shaped mold and cured sufficiently after some passage of time. Thus, in the construction industry related to the forming of a desired concrete structural shape there is considerable repetitive assembly and disassembly of the molds leading to the desire on the part of the construction industry to make this mold assembly/disassembly process as easy as possible. Breaking this down further on this easy mold assembly/disassembly issue it would be further desired that a minimum of time is required, a minimum of tools are required, and a minimum of waste (i.e. consuming disposables) is created.
As an example, in concrete flatwork wooden stakes are used to laterally retain the mold side edges having the disadvantages of consuming disposables (the wooden stakes) and the reliance on the soil rigidity (around the stakes) for the retaining of the mold, and as is usually the case the soil has been freshly displaced (due to excavation and refill) meaning that the soil can be too soft (non rigid) for later mold retention, thus requiring additional stakes to be used, which costs additional time and increases the consumables. This issue is significant as the force placed upon the mold from the freshly poured concrete can be very high depending upon the shape of the mold, further adding stress upon the mold shape retainer system and in addition if the mold should warp, distort, deflect, or even worse if the mold should rupture from the poured concrete force it is difficult to fix and as the concrete will cure in the distorted shape which will typically be unacceptable, necessitating a complete removal of the distorted concrete and replacement of the concrete structure. Thus is further made worse as the mold is typically in a planar shape which has weak resistance to bending or distortion as against its flat surface which is where the force exists from the freshly poured concrete.
Thus the need for retaining apparatus for concrete molds is well recognized in the prior art and also the desire for a quick and easy engaging/disengaging of the retaining apparatus as this engaging and disengaging process is done in a repeated manner many times. Starting with U.S. Pat. No. 5,234,654 to Brooks disclosed is a concrete forming system design primarily for flatwork, i.e. sidewalks that includes a beam that spans transversely across the side edge mold portions to retain the mold side edge portions at a desired distance, wherein the beam is positioned flat on the bottom or underneath the poured slab, i.e. with the beam being positioned external to the slab. While Brooks is functionally adequate it is overly complex in requiring fabricated pieces with multiple set holes taking more assembly/disassembly time that does not allow for an infinite range of spacing adjustment between the mold portions and the typical consumption of the beam being left under the concrete. Brooks, however, does have the advantage of having the beam and its form attachments underneath the slab, thus providing for unimpeded top slab surface finishing from the retaining apparatus. Further, in U.S. Pat. No. 6,234,447 B1 to Boyden et al., disclosed is a spacer for concrete form walls that is primarily design to “space apart” the form wall sections to help overcome the tendency of the upper portion of the form walls from angling inward from the force of the freshly poured concrete as against the form wall surface. Boyden et al., accomplishes this using a threaded spacer rod with movable end plates secured by nuts threadably engaged to the rod, while this arrangement allows for an infinite form spacing adjustment, it is more costly to make and has the potential for the threads to corrode and entrap small pieces of concrete which would greatly interfere with the smooth operation of the threadable engagement.
Continuing in this same area of the prior art in United States Patent Application Publication Number 2007/0069104 A1 to Morin disclosed is a concrete forming structure frame locking device that attaches to a form, facilitating adjustment between form portions by the use of telescoping nested channel pieces that are axially locked to one another by a threaded clamp that pinches together the channel pieces locking them in a selected telescopic extension. While somewhat similar to Boyden et al., with Morin allowing an infinite number of axial distance locking settings within the axial distance range of the telescoping channels, there are still the issues of corrosion and concrete interfering with the operation of the threads. Next, in looking at concrete form retainers that are disposed within the form interior i.e. being embedded within the concrete, in U.S. Pat. No. 6,918,567 B2 to Ward et al., disclosed is a concrete panel with gripping ribs and a provision for a sheathed tensioner cable between panels. Ward et al., is an example of having the double use of the cable being a form retainer and after the poured concrete has cured tensioning the cable to provide permanent rigidity to the concrete structure, with the drawback being the complexity, time and cost of the sheathed tensioning cable arrangement with the concrete form. Yet further, in another arrangement for reinforcing forms in U.S. Pat. No. 4,635,895 to Johnson, Jr. et al., disclosed is a concrete form spreader bracket that is used in conjunction with a braced stake, however, having the drawback of limited size adjustment of the bracket between the forms as the bracket is setup for basically a fixed configuration of form width and height in addition to not being particularly quick and easy to assemble or disassemble.
Continuing, in looking at the applicable prior art for form retainers, in U.S. Pat. No. 5,343,667 to Peden disclosed is a form brace that uses outrigger type support retainers with an over the top clamp for the concrete form panels, however being limited in form spacing variance that can be facilitated due to the length of the outriggers and the bracket size, thus flexibility of Peden in accommodating different form heights and widths is restrained. Similarly, in U.S. Pat. No. 7,076,925 B2 to Gagliano an integrated fitting is disclosed that is really designed to form a part of the cured concrete structure by anchoring the concrete structure into the earth in a cross rig type fashion somewhat like Peden, however, with the outriggers crossing one another for minimal space consumption outside of the form.
Yet further, in U.S. Pat. No. 4,066,237 to Bentz disclosed is a adjustable form stake assembly for holding a concrete form at a prescribed grade being a combination stake and spanning beam form holder, although in looking at the beam lying over the top edges of the form, finishing the top surface of the concrete would be difficult. However, again as in both Boyden et al. and Morin, Bentz has the undesirable feature of threaded connectors and/or retainers, that while allowing for infinite distance settings within a specified range for the form distance apart, however, the threads are not really practical in concrete work for the aforementioned reasons the threads becoming clogged with concrete and impairing their function. In a like design in U.S. Pat. No. 6,173,937 B1 to Cottongim disclosed is a cap clip and spreader for poured concrete wall forms, wherein the spreader acts to secure the wall forms, however, allowing a finishing trowel to pass underneath the spreader, however, having the drawback of requiring a special interface positioned on the top of the form for the spreader to attach to.
In a more traditional form of prior art for the retaining of concrete forms to one another looking at U.S. Pat. No. 4,247,073 to Vario disclosed is a concrete form tie assembly that is typically embedded in the poured concrete, the tie includes a rod with capped ends that are able to pre stress the rod axially with a wedge outside of the form and also has cone shaped sections that circumvent the rod on the inside edges of the form that push against a plate that substantially seals the opening in the form for the rod. The drawbacks of Vario include consumption of the tie in addition to having to penetrate the form and have extra hardware to secure, position, and seal the tie within the form. Similarly, in U.S. Pat. No. 7,144,530 B2 to Ward et al., disclosed is a concrete forming structure using threaded coupling slots that are engaged to a lattice framework that allows the threaded tie to be located almost anywhere along the form surface, however, again having the attendant disadvantages of a threaded interface as in the previously described Boyden et al., Morin, and Bentz.
What is needed is a simplified retaining apparatus having quick and easy assembly and disassembly, having an infinite range of adjustment within an allowable distance, requiring a minimum number of tools, having little or none consumable disposables, and not requiring a connection, penetration, or attachment therethrough any portion of the mold or form that would cause complication in so far as the interface with the poured concrete by causing an opening to seal or an additional removal step of the retaining apparatus from being partially disposed within the cured concrete structure.